Space telegraphy.



G. R. SAFPELL.

SPAGE TELEGRAPHY.

APPLICATION FILED AUG.12, 1909.

Patented Aug. 9,1910.

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UNITED STATES IATENT OFFICE.

CHESTER B. SAFFELL, OF THE UNITED STATES NAVY, ASSIGNOB TO JOHN FIRTH,OF NEW YORK, N. Y.

SPACE TELEGBAPHY.

Specification of Letters Patent.

Patented Aug. 9, 1910.

To all whom it may concern:

Be it known that I, Cnnsrnn R. SAFFELL, a citizen of the United States,electrician, of the United States Navy, have invented a new and usefulImprovement in Space Telegraphy, of which the following is aspecification.

My invention relates to space telegraph and its object is to provide aspace telegrap transmitting system in which the speed of rotation of thealternatin current generator which energizes the osci lation circuit andthe voltage developed by said generator may be maintained constant,irrespective of variations in the load applied to the same by theclosure of the transmittin key. In carrying out my invention I emp oymeans controlled by said key for increasing the energization of thefield of the generator or means controlled by said key for decreasingthe energization of the field of a motor mechanically connected withsaid generator, or I may employ both of said means.

My invention will be explained in connection with the accompanyin drawinwhich forms a part of thisspeci cation an illustrates diagrammaticallyone arrangement of apparatus and circuits whereby the foregoing objectsmay be carried into effect.

In the drawing the figure is a diagrammatic view representing a spacetelegraph transmitting system constructed in accord ance with myinvention.

In the particular diagram selected for more fully disclosing theprinciple of my invention, 1 represents a motor having brushes 20, 21fed by the direct current mains 2 2 and mechanically connected by theshaft 3 to the alternating current enerator 4.. This generator isconnecte in series with the primary 5 of a transformer, the transmittingkey 7 and its front contact 8. The secondary 6 of said transformer isconnected with the oscillation circuit which contains the condenser C,spark-gap S and primary I of an oscillation transformer. The secondary Iof this oscillation transformer is included in the antenna V which isconnected to earth at E. It will be understood of course that I do notlimit myself to the particular type of oscillation circuit shown or toany particular manner of associating said circuit with the antenna.

9 represents the field coil or coils (hereinafter referred to as thefield) of the motor 1 and is adjustably connected by the contact 11 withthe resistance 10, said resistance bemg connected with the brush 20 ofthe motor. A conductor connects the brush 20 of the motor at the oint 12to a metallic extension on the key said extension being insulated fromthe rest of the key by the insulation 14. The back contact 13 isconnected by the adjustable contact 11" to the resistance 10.

15 represents the field coil or coils (hereinafter referred to as thefield) of the alternating current generator 4 and is connected by theadjustable contact 16 to the resistance 17 one terminal of which isconnected to the brush 20 of the motor.

A supplemental front contact 19 of the key is connected by theadjustable contact 18 to the resistance 17.

The operation is as follows: Normally that portion of the resistance 10which is included between the contact 11' and the point 10, isshort-circuited by the extension of the key which. normally is heldagainst the back contact 13, the current passing from the main 2- to thepoint 10, thence to the point 12, contact 13, adjustable contact 11',through a portion of the resistance 10 to the contact 11 and thencethrough the field 9 and back to the source. As soon as the transmittingkey is depressed for the purpose of completing the circuit through theprimary 5' and thereby energizing the oscillation circuit, this shortcircuit is broken at 13 and that portion of the resistance includedbetween the adjustable contact 11' and the point 10 is included inseries with the field 9 thereby decreasing the energizetion of saidfield and increasing the torque of the motor, so that the speed of thelatter remains constant. Shortly after the extension of the key leavesthe contact 13, the circuit through the primary 5 is completed and theoscillation circuit is energized. When the load is applied by the keycontact 8 the motor is slowed down again, the positions of the contacts11, 11 being so chosen that. the speed of the motor under full-load withthe resistance between 10 and 11' in circuit is practically the same asthe noload speed with this resistance short-circuited. Thus'the speed ofthe generator is kept constant under conditions of rapldly' varyingno-load and full-load.

\Vhere a motor-generator consisting of a motor and a generator on asingle shaft is not employed, or if desired or rendered'necessary byvarious conditions where such motor-generator is employed, I may provldemeans cont-rolled by the transmitting key for increasing theenergization of the field of said generator, said means in thatembodiment of my invention above described consisting of the adjustableresistance 17 which is normally included in series with thefield 15 ofthe generator. When such arrangement is employed the operation is asfollows: Afterj the extension of the key leaves the contact 13 (if thelatter be employed) and in any event before the key 1tself makes contactwith the terminal 8, the said extension strikes the back contact 19thereby short-circuiting that portion of the resistance 17 which isincluded between the adjustable contact 18 and the point 18. The currentwhich energizes the field'15 then flows from the main 2 to the point 12by way of the point 10, through the extension of the key to the backcontact 19, thence to the adjustable contact 18 through a portion of theresistance 17 to the contact 16 and thence through the field 15 back tothe source. The resistance in series with the field 15 being reduced andthe energization of said field being increased, it follows that thevoltage developed by the alternator is increased so that when thecircuit of the primary 5 has been closed, the load thereby thrown on thegenerator will not reduce said voltage below that value which can beascertained and provided for by selecting the position of the contacts16 and 18 with respect to the resistance 17.

The apparatus above described whereby a rapidly varying load may beapplied to a generator is particularly adapted for Wireless telegraphtransmitting systems and is more efficient for the maintenance ofconstant speed and voltage than the various compound Wound motors andgenerators of commerce because the latter are not designed to take careof such rapidly varying loads as occurin a space telegra h transmittingsystem or for loads which have the Wide range of variation necessarilycreated during the operation of a wireless telegraph transmittingsystem.

It is not necessary to vary the resistances 10 and 17 directly by thekey 7, for it will be apparent that various arrangements of relays maybe introduced for accomplishing the same result and it will beunderstood of .be made by those skilled in the art, both in theapparatus and circuit arrangements herein described and illustrated,without departing from the spirit of my invention.

I clann:

1. A space telegraph transmitting system comprisingmn oscillationcircuit, an alternating current generator having a normally energizedfield associated with said oscillation circuit, a transmitting key, andmeans controlled by said key for increasing the energization of thefield of said generator.

2. A space telegraph transmitting system comprising an oscillationcircuit, an alternating current generator associated therewith, a motormechanically connected with said generator, a transmitting key and meanscontrolled by said key for decreasing the energization of the field ofsaid motor.

3. A space telegraph transmitting system comprising an oscillationcircuit, an alternating current generator associated therewith, a motormechanically connected with said generator, a transmitting key, meanscontrolled by said key for increasing the energization of the field ofsaid generator, and other means controlled by said key for decreasingthe energization of the field of said motor.

4. A space telegraph transmitting system comprising an oscillationcircuit, an alternating current energized field associated with saidoscillation circuit, a transmitting key and means controlled by said keyfor increasing the voltage developed by said generator.

5. A space telegraph transmitting system comprising an oscillationcircuit, an alter nating current generator associated therewith, a motormechanically connected with said generator, a transmitting key and meanscontrolled by said key for increasing the torque of said motor.

6. A space telegraph transmitting system comprising an oscillationcircuit, an alternating current generator associated therewith, a motormechanically connected with said generator, a transmitting key, meanscontrolled by said key for increasing the voltage developed by saidgenerator and other means controlled by said key for increasing thetorque of said motor.

7. A space telegraph transmitting system comprising an oscillationcircuit, an alternating current generator associated there- -with, atransmitting key, a resistance in series with the field of said meanscontrolled by said key said resistance.

8. A space telegraph transmitting system comprising an oscillationcircuit, an alternating current generator associated there with, a motormechanically connected with said generator, a transmitting key, aresistenerator and or decreasing generator having a normallyanoe inseries with the field of said motor and means controlled by said key forincreasing said resistance.

9. A space telegraph transmitting system comprising an oscillationcircuit, an alternating current generator associated therewith, a motormechanically connected with said generator, a transmitting key, a re-'sistance in series with the field of said generator, means controlled bysaid key for decreasing said resistance, a resistance in series with thefield of said motor and other means controlled by said key forincreasing the last mentioned resistance.

10. A space telegraph transmitting system comprising an oscillationcircuit, an alternating current generator associated therewith, atransmitting key, an adjustable resistance' i'n series with saidenerator and means controlled by said key or decreasingsaid resistance.

11. A space telegraph transmitting system comprising an oscillationcircuit, an alternating current generator associated therewith, a motormechanically connected with said enerator, a transmitting key, andadjusta 1e resistance in series with the field of said motor and meanscontrolled by said key for increasing said resistance.

12. A space telegraph transmitting system comprising an oscillationcircuit, an alternating current generator associated therewith, a motormechanically connected with said generator, a transmitting key, anadjustable resistance in series with the field of said generator, meanscontrolled by said key for decreasing said resistance, an adjustableresistance in series with the field of said motor and other meanscontrolled by said key for increasing the last mentioned resistance.

In testimony whereof, I have hereunto subscribed my name this 11th dayof August 1909.

CHESTER R. SAFFELL.

Witnesses:

E. B. TOMLINSON, Gno. K. WOODWORTH.

